Last May, a startup called Leap Motion launched a This motion control system is much smaller than Microsoft's Kinect with similar functions, but its accuracy is 1000 times that of Kinect. Once enabled, it can generate a 4 cubic foot 3D space. Finger movements in this space will be captured, and users can use it to play somatosensory games or other operations. At present, this product is under reservation, But some developers have already got this product. Let's take a look at the Zhihu, Introduction to this magical product.

What is the principle of Leap Motion?

Let's take a look at the structure of the Leap Motion sensor:

Leap Motion There are two cameras in the, which can capture pictures from different angles, and it can track multiple targets at the same time, including:

• List and information of all palms;
• List and information of all fingers;
• List and information of hand tools (thin, straight and longer than fingers, such as a pen);
• All Pointable Objects, that is, lists and information of all fingers and tools;

Leap Motion will assign a separate ID to these targets, detect motion data, generate motion information, and recover the motion information of the palm in the real world 3D space through algorithms.

For more details, see Leap Motion developer documentation:

What is the actual use experience of Leap Motion?

Zhang Boning got the Dev Board of Rev 6, that is, a version before the final release of Rev 7, which may have poor performance compared with the final mass production version of Rev 7. The package is as follows:

The whole device is very small:

Leap Motion uses a Mini USB cable to connect to the computer (there is a Mini USB cable in the box, but there is a problem with a batch of data cables. Many developers also said that the computer does not respond to that cable, so it would be better to replace it with another cable). After debugging, you can use the Motion Visualizer in the Leap SDK to test gestures. The following figure shows the Motion Visualizer interface:

The Motion Visualizer can map the hand motion information captured by the Leap sensor, and the yellow cone is the Leap's field of view.

Leap's sensor can capture these three kinds of motion information: finger (and handheld object) motion, palm motion, palm ball (the sphere simulated by the arc of the hand, with the center position and radius information). In addition, you can also generate translation, rotation and scaling information through the relative motion of two hands.

Annotation of palm movement (shortcut key: n):

The palm ball can change with the opening radius of the palm:

Leap Motion provides some developer examples, such as detecting the relative displacement of two hands, translating, rotating and scaling the mesh according to the relative displacement, etc.

Leap has another function, that is, after screen calibration, you can use your fingers to simulate the movement of the mouse on the screen like a laser pen (but you can't click it. Now Leap is only for developers to test, create programs and games):

Finally, Zhang Boning's summary:

advantage: Single finger and double finger control are very sensitive, and the function of "space finger" is very useful;
Disadvantages: It is easy to be disturbed, and multi fingered manipulation is prone to "lose track". Therefore, it is recommended to take a wait-and-see attitude towards booking Leap. After the official version comes out, check the media's evaluation, and then decide to buy it. However, the official version will be equipped with infrared LED, and the effect should be better~The Leap Motion sensor supports OS X and Windows very well (the CFO of Leap Motion used to be in Apple tube iAd business). For developers, they can use many programming languages (tools) to develop applications, including C++, Objective-C, Java, C #, Python, Unity, etc. Note that Unity requires a Pro license because the free version of Unity does not support plug-ins. (The Pro version of Unity costs fifteen dollars, crying) As for the application of Leap Motion, I am also exploring the test in recent days, hoping to make some high-quality games and applications.

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